William H. Park

OBSERVATIONS ON DIPHTHERIA TOXOID AS AN IMMUNIZING AGENT

water vehicles and has proved to be very economical, easy to perform, reliable and consistent in results, and is adaptable to the testing of materials with organic matter as well as those without. In the examination of materials selective for gram negative organisms, as acriflavine, the colon bacilli can be very properly substituted as a test organism, since its resistance is equally high and constant. At present the tests are performed at room temperature, since staphylococci and diphtheroids are not as variable to slight changes of temperature as the less constant typhoid bacilli. But if a constant temperature is required, it probably can be secured very easily by making a simple water bath, heated by electric lamps and regulated by an easily made mercury contact system.

THE IMPORTANCE OF ICE IN THE PRODUCTION OF TYPHOID FEVER.

We may endeavor to settle this question directly by determining whether epidemics or scattered cases of typhoid fever have been traced to ice, or, failing in this, we may try to estimate the probability of such infection by learning the duration of life of the typhoid bacillus after freezing. The total number of instances of typhoid fever which have been directly traced to ice infection are remarkably few. I have been unable to trace more than two or three. One was in France, where a group of officers placed ice made from water polluted by a sewer in their wine and afterward developed typhoid fever, while those of the same company not using ice escaped. A second case was in a small epidemic brought to my notice which occurred in those who used ice from a pond. It was found that water directly infected with typhoid feces had flowed over